Luminescence characteristics and energy transfer of Eu2+/Tb3+ doped single phase multi-color phosphor

The investigation on single phase multi-color phosphors is highly meaningful for near-ultraviolet chip based white light emitting diodes. In this work, a series of Eu2+ and Tb3+ singly doped and Eu2+/Tb3+ codoped Sr5(PO4)3Cl phosphors were synthesized via a high-temperature solid state reaction method. The luminescence spectra and decay curves of Eu2+ and Tb3+ singly doped samples were discussed, the optimal doping concentrations were determined. Thanks to the spectra overlap between Eu2+ and Tb3+, nonradiative energy transfer from Eu2+ to Tb3+ was investigated. It is found electric dipole-dipole interaction played the main role for the energy transfer in codoped samples, the highest energy transfer efficiency was calculated to be 60.98%. Tunable emissions are observed for codoped samples by adjusting doping concentration. The thermal quenching properties were discussed and the activation energy (ΔE) was estimated in the present work.